第一性原理计算Al原子及空位掺杂6H-SiC的电子结构和磁性能（英文）

Electronic Structures and Magnetic Properties of Al-and Vacancy-doped 6H-SiC: A First-Principles Study

基于密度泛函理论的第一性原理,研究了6H-SiC的不同掺杂体系如碳空位(V_C)掺杂体系、硅空位(V_(Si))掺杂体系及(Al,V_(Si))共掺杂体系的电子结构和磁性。结果表明:单独的V_C或V_(Si)掺杂体系具有微弱的磁性,而(V_C,V_(Si))共掺杂体系呈现出强烈的磁性,其原因归结于V_C和V_(Si)之间强烈的耦合效应,致使碳原子附近的空位产生强烈的自旋极化。虽然在Al原子单独掺杂6H-SiC的体系中没有发现磁性,但是(Al, V_(Si))共掺杂体系具有明显的磁性,表明磁性并非源于Al原子的3p轨道,而是来源于C原子的2p轨道。研究结果为6H-SiC在稀磁半导体自旋电子器件上的潜在应用提供理论依据。

Using the first-principles method based on density functional theory(DFT),we studied the electronic structures and magnetic properties of 6H-SiC with different doped systems,such as a C vacancy(VC)-doped system,a Si vacancy(VSi)-doped system,and an(Al,VSi)-codoped system.The results show that the single VC-or V Si-doped 6H-SiC system exhibits weak magnetism,while the(VC,VSi)-codoped 6H-SiC system exhibits strong magnetic properties because of the intense coupling between VC and VSi,leading to nearby C vacancy atoms producing strong spin polarization.Although the Al atom alone does not induce magnetism in the Al-doped 6H-SiC system,the(Al,VSi)-codoped 6H-SiC system appears to have magnetic properties,indicating that the origin of magnetism is not from the Al:3p orbital but from the spin polarization of the C:2p orbital.These results provide a route for potential applications of dilute magnetic semiconductors in spintronic devices by employing doped 6H-SiC.